Motor Vehicle Turbo or Supercharger Diverter Valve System

ABSTRACT

Turbo or super charged intake tract diverter valve system, upstream of a throttle valve, includes a closure means (10) for a diversion aperture (4.1) in the intake tract (3) to vent pressurised gases within to a bypass path or atmosphere; the closure means having a transfer aperture (12) facilitating a net three due to a pressure differential on its opposite sides of the closure means (10) so as to close or keep closed the diversion aperture (4.1). When gas pressure on opposite sides of the closure means is equal, and when an upstream side (10.1) of the closure means (10) has a pressure greater than a downstream side (5.1), then it will open the diversion aperture (4.1). An actuation means opens a control aperture (6) to create the necessary pressure differential on the closure means (10) to thereby cause same to open the diversion aperture (4.1).

FIELD OF THE INVENTION

The present invention relates to diverter valve systems used withturbocharged or supercharged motor vehicles.

BACKGROUND OF THE INVENTION

Most modern turbocharged vehicle engines include some form offactory-fitted blow-off or bypass valve in the intake tract, the purposeof which is to open during throttle closure to provide a relief pathfrom a diversion aperture for pressurised air that would otherwise causesignificant pressure spikes, resulting in damage or reduced life-span ofthe turbocharger, and also an unpleasant fluttering noise that is deemedunacceptable in a road-going passenger car.

There is also a potential performance improvement, in that without arelief path, rapid throttle closure and the resulting pressure spike canrapidly slow the turbo compressor, leading to a longer delay inreturning to peak boost when the throttle is re-opened (i.e. increasedturbo lag). Similarly, allowing the bypass valve to relieve too muchpressure can also have an adverse effect on turbo lag—evacuating theentire volume of the intake tract means that despite maintaining ahigher compressor speed over the short term, when the throttle isre-opened the intake tract must be re-pressurised which causes anincrease in lag.

Many factory-fitted bypass valves perform additional tasks, such aslimiting boost pressure for engine protection in the event ofhigher-than-normal boost pressure being detected, and momentary powerreduction when required for traction control or during a gearshift inthe case of automatic transmissions.

Factory or OEM fitted bypass valves. Until recently, most factory-fittedbypass valves have been located somewhere on the engine's intake tractdownstream of the turbo compressor, usually being mounted either by hoseor flange connection. The vented air from the bypass valve is thendirected back to the turbo compressor intake via another hose or duct,thus forming a bypass loop around the compressor.

Newer implementations include a mounting flange built directly into theturbo's compressor cover, which includes separate paths for both theincoming pressure and the vented air to be recirculated in the oneflange.

The factory bypass valve can be fitted to this type of flange, and is adirect-actuated solenoid type, that is controlled by a signal from thecar's Engine Control Unit (ECU). This type of valve features an electricsolenoid coil which has a plunger, on which plunger is mounted a valvemember to open or close the diversion aperture in the intake tract. Theplunger and valve member is biased to the closed position by a spring.When the solenoid is energised, this pulls the plunger into the solenoidcoil against the bias of the spring, and the valve member will thus openthe diversion aperture. When de-energised, the plunger and the valvemember are returned by the spring to the closed condition. In thissystem the plunger is connected directly to valve member that opens andcloses the diversion aperture and thus bypass path.

The OEM system operates as follows: the ECU monitors the acceleratorpedal position, and if a rapid reduction in accelerator pedal positionis detected, the ECU energises the solenoid coil to open the valvemember and thus the bypass path. The ECU typically holds the bypassvalve open for approximately 2 seconds, unless it detects that theaccelerator pedal position is increased, at which point it willimmediately de-energise the solenoid coil and thus close the diversionaperture and the bypass path.

There are three known versions of the factory diverter valve used: thefirst type uses a diaphragm and poppet-style valve that is connected tothe solenoid plunger. There are holes in the face of the piston thattransfer pressure to the back of the diaphragm in order to balance theopposing forces that result from the pressure acting on the areas infront of and behind the diaphragm, so that the sum of the forces istheoretically zero. This then means that when energised, the solenoidcoil is able to pull the plunger, diaphragm and poppet valve openagainst the return spring, thereby opening up diversion aperture and thebypass path. When the solenoid is de-energised, the return springreturns the plunger, diaphragm and poppet valve to the closed position.

The second type uses a plastic piston type valve that is corrected tothe solenoid plunger. Again, there are holes located in the face of thepiston to equalise pressure front and back, thereby theoreticallycreating no resultant force. It operates in the same way as thediaphragm type described above.

The third type is the same as the second type, except it features aslotted “basket” that shrouds the piston. Its purpose can only beassumed to aid closure when the piston is open and the solenoid is thende-energised.

Deficiencies of factory-fitted bypass valves. These factory-fittedbypass valve types all share a common operating principle, which isprimarily designed to eliminate pressure spikes and the associatednoise. The ECU can only operate the solenoid in two states—on or off.Therefore, because the valve is directly connected to the solenoidplunger in all cases, the valve can only be open or shut. No method isprovided for varying the opening size in response to the pressure in theintake tract, and as a result, turbo lag on these cars is less thanoptimised.

In addition, the evolution of the factory-fitted bypass valves indicatesthat there are inherent deficiencies in the design of the valve itself.

An inherent deficiency with the first type is that it is commonly knownto fail even under normal operating conditions by rupturing of thediaphragm or tearing of the face seal on the piston. The second andthird types seek to solve this problem of torn diaphragms, however thefact that the piston is made from plastic means that a close tolerancedfit cannot be achieved between the piston and the sleeve. Since there isno diaphragm to seal this gap, a significant amount of air is able toleak from the rear chamber of the piston past the gap and into therecirculation path. This situation is less than ideal for performance,since pressurised air is being lost. Secondly, the piston type valvesuffers a condition where it is unable to close, resulting insignificant power loss. Once opened and when there is significant airbeing bypassed, if the throttle is re-opened very quickly and thesolenoid de-energised, the piston is unable to close because of the weakreturn spring and the un-balanced forces on the piston caused by dynamicpressure of air rushing past the face of the piston—under theseconditions there is a greater pressure acting on the face of the pistonthan there is on the back of the piston, causing it to be held open. Theonly way to get it to close again once this happens is to close thethrottle once again until the bypassing air pressure drops enough to letthe piston close.

The third type is a further evolution of the second type, with thevented “basket” a clear attempt to diffuse the bypass air to reduce itsvelocity so it can enter the transfer holes in the face of the piston inorder to balance the forces and allow it to close. Unfortunately, thissolution is only moderately effective, and certain conditions can stillcause this valve type to be held open.

All of the above deficiencies of the three types of factory-fittedbypass valve are especially noticeable when the car has been modified toincrease performance through higher boost pressure, as this is oftenassociated with higher intake temperatures that can accelerate therupture of the diaphragm type, and exacerbate the non-closure issue andleaking of the piston types.

After Market Valves: there are two common approaches taken byaftermarket bypass valve manufacturers to solve the problems of thefactory-fitted bypass valves. Both methods involve replacing the entirefactory-fitted solenoid coil and valve entirely with apneumatically-operated valve. Where the two methods differ however ishow the pneumatic valves are controlled.

One method supplies a 3-port solenoid valve that alternately connects avacuum source and a pressure source to the pneumatic bypass valve—vacuumcauses the bypass valve to open, pressure makes it close. The 3-portsolenoid valve supplied with this kit connects to the factory wiringharness in the engine bay so it utilises the same signal from the ECU todetermine when to open the bypass valve.

The second method does not use the ECU signal at all. Instead, it simplyconnects the bypass valve directly to the intake manifold, therebycausing the valve to open when the throttle is closed and the intakemanifold is in vacuum, and when the throttle is open the intake manifoldis pressurised and therefore the bypass valve is closed. This is thecommon method used by most after-market bypass valves.

Deficiencies of After-Market valves: despite both methods used in theafter-market valves ensuring the deficiencies of the factory-fittedbypass valve are overcome (i.e. robustness, preventing boost pressureleaks, and the ability to close when required), these methods have theirown set of deficiencies that cannot be overcome regardless of the designof the hardware.

The first method retains the ECU control, which is desirable for rapidresponse of the bypass valve opening, however to achieve this, theapparatus supplied in order to carry out this method is extensive,expensive, and time-consuming to install. The apparatus required tocarry out the first method must include: a means to provide a hoseconnection to the intake manifold; a 3-port solenoid valve; a means ofelectrically connecting the 3 port solenoid valve to the factory wiringharness; a mounting bracket to hold the 3 port solenoid valve in place;sufficient lengths of vacuum hose to connect the 3 port solenoid valve,and a pneumatically-operated bypass valve. Installation of thisapparatus requires significant time, typically at least an hour by anexperienced vehicle mechanic.

Even once the above apparatus is installed, there is a key performancedeficiency in reaction time. The addition of the 3 port solenoid valveand the associated lengths of vacuum hose connecting it to the bypassvalve mean that there is a time delay between the ECU energising the 3port solenoid valve and the bypass valve opening. This is furtherhindered by the fact that this apparatus still requires a vacuum beforethe bypass valve can begin to open—even when the 3 port solenoid hasswitched the source to the intake manifold, the throttle needs to bemostly closed before the intake manifold has sufficient vacuum to openthe bypass valve. By this time a pressure spike may have alreadyoccurred.

The second method suffers similar deficiencies. The apparatus requiredto carry out the second method must include: a means to provide a hoseconnection to the intake manifold; a means to provide an electricalballast load to the factory wiring harness to prevent the ECU fromdetecting a bypass valve fault since the factory-fitted solenoid coilhas been removed; sufficient lengths of vacuum hose to connect theintake manifold valve to the bypass valve; a pneumatically-operatedbypass valve. Like the first method, installation of this apparatusrequires significant time, typically at least an hour by an experiencedvehicle mechanic.

This method also suffers from delayed opening time for the same reasonas the first method—the apparatus requires the intake manifold toachieve sufficient vacuum to aid bypass valve opening, by which time apressure spike has already occurred.

Both methods require additional apparatus, which adds significant costto the kit, complexity and time of installation, and therefore increasedcost of installation. All of this comes at the expense of a delayedresponse time of the bypass valve, thereby failing to achieve one of theprimary purposes of a bypass valve.

Any reference herein to known prior art does not, unless the contraryindication appears, constitute an admission that such prior art iscommonly known by those skilled in the art about which the inventionrelates, at the priority date of this application.

SUMMARY OF THE INVENTION

The present invention provides a or super charged intake tract divertervalve system having a valve body adapted to be sealingly mounted to saidintake tract upstream of a throttle valve associated with said intaketract, said body including a closure means to operatively close off adiversion aperture in said intake tract so as to vent pressurised gasesin said intake tract to a bypass path or atmosphere at predeterminedtimes, said system including an actuation means to allow said closuremeans to open whereby pressurised gases in said intake tract will passthrough said diversion aperture into said bypass path or to atmosphere,characterised in that said closure means includes a chamber associatedwith said valve body and a valve member which cooperates with saidchamber to close said diversion aperture, said valve member including atleast one transfer aperture through it, said valve member beingconfigured so that by means of said pressurised gases, said valve memberhas a net force provided from a surface area differential with respectto opposite sides of said valve member so as to close said diversionaperture or keep it closed, when gas pressure on opposite sides of saidvalve member is equal, and when a pressure differential is created sothat an upstream side of said valve member has pressure greater than adownstream side, then said valve member will move to open said diversionaperture, said system including said actuation means associated withsaid chamber or said valve member, whereby when controlled to do so saidactuation means will open a control aperture associated with saidchamber or said valve, to thereby create said pressure differential onthe valve member to thereby cause same to open said diversion aperture.

The valve member can be a generally hollow piston with said hole beingthrough an otherwise closed off end of said piston.

The chamber can be formed from side walls attached to said valve body,and said piston.

The valve member and said chamber can be of a generally cylindricalconstruction.

The ratio of cross sectional area of said transfer aperture with respectto the cross sectional area of said control aperture is less than orequal to 1:2. This can be said another way, namely that the crosssectional area of the control aperture is at least twice the magnitudeof the cross sectional area of the transfer aperture in the valvemember.

The surface area of said valve member on the upstream side, which isdirectly exposed to said pressurised gas, is less than the surface areaof said valve member op the downstream side which is exposed to saidpressurised gas via said transfer aperture.

The surface area on the downstream side of said valve member can be oneor more of the following: at least 10% greater than that of the upstreamside; at least 20% greater than that of the upstream side; at least 30%greater than that of the upstream side.

The actuation means can be activated by a vehicle's engine control unitor ECU.

The actuation means can include a solenoid, or a control valve membercooperating with a solenoid, to open or close said control aperture.

A return spring can be provided between one end of said chamber and saidvalve member so that said valve member when in a closed condition hasone of the following: no pre-load force from the return spring; thepre-load force is in the range of greater than zero and up to 0.2 kg.

The spring provides a pre-load force greater than zero, so as to urgethe valve member to close said diversion aperture at an appropriatepressure differential.

The return spring can provide said valve member with a stroke lengthwhich is dependent upon the amount of pressure located in said intaketract.

The diversion aperture can remain fully closed when the pressure in saidtract is not sufficient to open said valve member against said returnspring even when the vehicle's engine control unit is energising theactuation means.

The diverter valve system as described above can be provided and orconstructed as an OEM component or assembly.

The diverter valve system as described above can be provided orconstructed as an after-market component or assembly, in which case thevalve can be constructed from a kit of parts, which utilises a vehicle'soriginal factory fitted solenoid coil, and valve mounting flange.Further, the vehicle's original factor fitted solenoid return spring canalso be utilised or as is most preferred a stiffer spring than thefactory one can be provided.

The actuation means can be located in the valve body adjacent the valvemember or the actuation means can be located in a body remotely locatedfrom said body having said valve member, in which case between said bodyremotely located from said body having said valve member and said bodyhaving said valve member the respective ports are interconnected bymeans of flexible tubing.

The present invention also provides a method of operating a turbo orsuper charged intake tract diverts valve system, said method comprisingthe steps of providing a piston to open and close a diversion apertureof a bypass path, said piston having a transfer aperture through it, andan upstream surface area adapted to be in contact with a pressurised gason an upstream side of said diversion aperture, which upstream surfacearea is less than a downstream surface area which will act underpressure of gas passing through said transfer aperture, providing achamber to cooperate with said piston which has a control aperturetherein, said method including the step of closing or opening saidcontrol aperture by means of an actuatable valve member, to allow saidpiston to open or close said diversion aperture.

A return spring can be provided between a portion of said chamber andsaid piston so that said piston will have its stroke length dependentupon the amount of pressure located in said intake tract.

The diversion aperture can remain fully closed when the pressure is notsufficient to open when the vehicle's engine control unit is energisingthe solenoid.

The present invention further provides an automobile engine having aturbo or super charged intake tract diverter valve as described above orhas a diverter valve that operates by the method described above.

The present invention also provides an automobile having an automobileengine as described above.

BRIEF DESCRIPTION OF THE DRAWINGS

An embodiment or embodiments of the present invention will now bedescribed, by way of example only, with reference to the accompanyingdrawings, in which:

FIG. 1 illustrates a cross section through a turbo or super chargedintake tract diverter valve, in the closed condition.

FIG. 2 illustrates a view similar to FIG. 1, identifying additionalcomponent and indicating the piston inside and outside diameters.

FIG. 3 illustrates an exploded cross sectional view of the components ofFIGS. 1 and 2.

FIG. 4 illustrates a cross section similar to FIG. 1, with the controlaperture open and the valve member in the open condition.

FIG. 5 illustrates a cross section through a valve in a closedcondition, similar to that of FIG. 1, except that a return spring is notutilised.

FIG. 6 illustrates a cross section of the valve of FIG. 5 in the opencondition, due to the control aperture being open by the solenoid.

FIG. 7 illustrates a cross section through a prior art diverter valvesuch as that which is factory fitted or is an OEM valve.

FIG. 8 illustrates an upper perspective view of the valve body 4 of theFIGS. 1 to 5 valve arrangements.

FIG. 8A illustrates a side view of the valve body 4 of FIG. 8.

FIG. 9 illustrates a lower perspective view of the valve body of FIG. 8.

FIG. 10 is a perspective partial cross section through the piston 10 ofthe previous Figures showing m more detail some of the features of thepiston.

FIG. 11 is a cross sectional view through a valve system which has someparts of the valve of the previous embodiments located remotely fromother parts.

FIG. 12 is a block diagram of the operation method of the diverter valvesystem of the present invention.

DETAILED DESCRIPTION OF THE EMBODIMENT OR EMBODIMENTS

As illustrated in FIGS. 1 and 2, the diverter valve system comprises avalve body 1 whose outer profile conforms to that of a vehicle's factoryfitted solenoid coil body 2 and that of the mounting flange 3 which maybe on the turbocharger compressor or other component of the enginesintake tract, so that the valve body 1 is sandwiched between body 2 andflange 3.

The valve body 1 contains a cylindrical wall 4 that is part of a bypasspath 9 that leads back to the turbocharger compressor inlet. The wall 4includes a chamber 5.1 which is formed by upper cylindrical wall 5.2 ofcylindrical wall 4 and which is closed off by a wall 5 at the end withinthe valve body 1. The wall 5 contains a control aperture or hole 6, thatallows the passage of air through it into a chamber 7 on the other sideof the wall 5, and is bounded by the face of the solenoid coil body 2when assembled. At least one transfer passage or passages 8 are includedin the valve body 1 so as to allow passage of air from the chamber 7 tothe outside of the valve body 1, via the recirculation passage or bypasspath 9 when the valve is installed on a vehicle. It will be noted fromFIGS. 1 and 8 that the cylindrical wall 4 is formed in a frusto-conicalformation 1.6, and that the lowermost rim 1.5 of this formation 1.6, islocated at a distance (see arrow 4.2 in FIG. 4) of approximately 5 mm.This distance is the same distance measurement which the piston valve ofFIG. 7 will open to. Further this distance of 5 mm will produce anopening to allow air for the diversion aperture 4.1 to directly flowthrough into the path 9, such that diversion aperture 4.1 and thepassage past the rim 1.5 are of similar cross-sectional areas, therebypreventing the rim from obstructing flow into the bypass passage 9.

From FIGS. 8 and 8A it will be noted that the four transfer passages 8are angularly equi-spaced around the circumference of the frusto-conicalportion 1.6, with centres located on a concentric pitch circle diameter,and thus radially outwardly of the cylindrical wall 4, which produces anelliptical exit port from each of the passages 8. Four transfer passagesare used in the embodiment of FIGS. 8 and 8A because of the thickness ofthe wall though which the transfer passages pass, and othermanufacturing reasons. However, it will be understood that the number oftransfer passages is not critical as long as the flow through thetransfer passage or passages does not impede the flow of air from thecontrol aperture, as described in paragraph [081] below. As will also bedescribed in a later embodiment when the body is split so that the valvebody and actuator body can be remotely located, a single transferpassage connected by silicone hose will suffice, provided it is of adiameter large enough to permit the required air flow. Thus, the numberof passages or the size of a transfer passage is such that there must besufficient cross-sectional area so as not to impede flow. A cylindricalpiston 10, illustrated in detail in FIG. 10, is formed by a hollowcylinder with a substantially closed-off end 10.1. The piston 10 isconfigured to fit inside the chamber 5.1 with a fit as close a practicalto allow free axial movement, typically 0.015 mm-0.05 mm clearance. Theclosed-off end 10.1 further comprises a face seal 11 which willpreferably include a circumferentially arranged bonded silicone bead,for sealing against the floor of the recirculation passage or bypasspath 9 when installed, so as to close off the diversion aperture 4.1 atthe start of she bypass path when the piston 10 is in the closedposition. The closed-off end 10.1 further comprises a transfer orbalance aperture 12 that allows passage of air from the upstream side ofthe piston face (that is on the diversion aperture 4.1 side) to thedownstream side which is on the inside of the piston 10. Importantly,the cross-sectional area of this transfer or balance aperture 12 willneed to be at least 2 times smaller than the control aperture or hole 6in the wall 5 of the valve body bore. Further the surface area of theface 10.2 of the piston closed off end 10.1, defined by the contactperimeter of face seal bead 11, should be at least approximately 22%smaller in magnitude than the overall surface area calculated based onthe outside diameter of the piston 10 (i.e. piston OD:face seal area is1:0.78). In terms of ratio of diameters this equates to the diameter ofthe surface which closes the diversion aperture is about 0.885 the sizeof the outside diameter of the piston 10. Another way to say this isthat the effective area of the piston 10 on which the pressure acts onthe back or downstream side is approximately 27% larger than theeffective area of the piston on the upstream side defined by the bondedsilicone face seal 11.1 that closes the diversion aperture 4.1, (that isthe ratio of face seal surface area to OD surface area is 1:1.27). Thissurface area differential with respect to opposite sides (namely theupstream and downstream sides) of the piston 10 will ensure that thepiston 10 closes the diversion aperture 4.1 or keeps it closed, when gaspressure on opposite sides of the piston 10 is equal.

While it is preferred that there is only a single transfer or balanceaperture 12 illustrated, it will be readily understood that more thanone transfer or balance aperture 12 could be used, if more than one isused, then the sum of the cross sectional areas of each of the apertureswill need to total at least 2 times smaller (that is be 50% or less)than the control aperture or hole 6 in the wall 5 of the valve bodybore.

As best seen in FIG. 2, a steel solenoid plunger 13 is designed, sizedand shaped so as to fit onto the spigot 14 of the factory-fittedsolenoid coil 2 when assembled, with provision for the factory returnspring 15. The plunger 13 further comprises a face seal or O-ring 15that ensures the control aperture or hole 6 in the wall 5 of the valvebody 1 is closed off and sealed when the plunger 13 is in the closedposition when the factory-fitted solenoid coil 2 is de-energised. AnO-ring 17 is provided so as to cushion the retraction travel of theplunger 13 when the solenoid coil is energised, in order to prevent anaudible “clack” sound which would otherwise be heard.

A main return compression spring 18 of suitable dimensions andspecification is provided so as to produce additional bias or returningforce to the piston 10. It is preferred that the return spring providesno pre-load when the piston 10 is in the closed position, or if apreload is provided it is greater than zero but up to and preferably notexceeding 0.2 kg of pre-load when the piston 10 is in the closedposition, such as for the vehicles mentioned below. Pre-load is nil orif present is kept in the narrow range described so as to prevent orminimise the occurrence of turbo compressor surge. The spring rateshould be such that the spring force is between 1-1.5 kg at maximumpiston lift for such vehicles. However, for other vehicular enginesthese spring parameters may vary in accordance with the pressures in thesystem and other factors like the turbo specification. The exact springforce and rate (which is a function of spring dimensions) may need to bedetermined by trial and error to determine a maximum pre-load on thepiston 10 prior to the onset of compressor surge. It is believed that nomore than 0.2 kg of preload will prevent or minimise such compressorsurge.

The compression return spring 18 can be given no pre-load in the valvesystem assembly by either the piston 10 being sized such that thedimensions of the chamber 5.1. or the non compressed height of thespring is sized, so that when piston and spring is assembled, and thepiston 10 has closed off the diversion aperture 4.1, the return spring18 is in an uncompressed state. Another way to ensure that no preload isprovided by the return spring 18, is to have the uncompressed height ofthe spring 18 less than the height of the chamber 5.1 when the piston 10is in the closed off position relative to the diversion aperture 4.1.This will ensure that for the last part of the stroke of the piston 10to the closed position that the piston 10 is not under the urging of thereturn spring 18.

The valve of FIGS. 1 and 2 can be constructed on an existing vehicle byremoving some of the components of the original diverter valve, and byutilising the original factory-fitted solenoid coil 2. Thefactory-fitted valve mechanism once removed from the solenoid coil canbe discarded. Also used is the factory-fitted solenoid return spring 15,and the mounting flange 3, which may be integrated into the turbochargercompressor cover, or may be remotely mounted and connected to the intakesystem via hoses depending upon what is present on the original vehicle.The components described above are then assembled onto the mountingflange as illustrated in the exploded view of FIG. 3.

Operation of the apparatus: Whenever the solenoid coil 2 isde-energised, the solenoid plunger 13 remains in a closed position asillustrated in FIGS. 1 and 2, by means of the return spring 15, thusensuring the piston 10 and bore or chamber 5.1 define an essentiallyclosed volume, at its downstream end. When boost pressure is present inthe turbo system and this is communicated to the upstream face of thepiston 10 (upstream relative to the transfer aperture 12), the samepressure is also transferred through the transfer aperture 12 throughthe closed end 10.1 of the piston 10 into the closed volume behind thepiston or the downstream side of the closed end 10.1 and transferaperture 12. Since the effective area of the piston 10 on which thepressure acts on the back or downstream side is approximately ofpreferably 27% (face seal surface area:OD surface area is 1:1.27) largerthan the effective area of the piston on the upstream side, defined bythe bonded silicone face seal 11.1 that closes the diversion aperture4.1, there is an imbalanced or net force that pushes the piston 10 toclose against the upper rim of the diversion aperture 4.1 on themounting flange 3. Regardless of how high the boost pressure is or maybe, the piston 10, due to this arrangement, will always be pushed closedby a force which is 27% greater than the force it would otherwise bepushed open with.

When the ECU energises the solenoid coil 2, the solenoid plunger 13 isretracted, thereby opening the control aperture or hole 6 in the wall 5of the valve body 1, as is best illustrated in FIG. 4. Air which isunder pressure is then allowed to flow out of the chamber 5.1 and intothe chamber 7 defined by the valve body wall 5 and the solenoid coilbody 2. This air can then pass unimpeded through the transfer passages 8into the recirculation chamber or bypass path 9, which is typically atatmospheric pressure. Because the transfer aperture 12 in the closed end10.1 of the piston 10 is smaller than the control aperture or hole 6 inthe valve body wall 5 and the transfer passages 8, the pressure withinthe chamber 5.1 defined by the piston 10 and valve body or walls 5.2will be sufficiently reduced to allow the imbalance of forces, or netforce, to push the piston 10 open. When the piston 10 is in the openposition, recirculation of the pressurised air by means of the bypasspath 9, can take place to prevent pressure spikes in the intake tract.

When the ECU de-energises the solenoid coil 2, the plunger 13 moves backunder the bias of the spring 15 so as to close the control aperture 6and once again seals the valve body chamber 5.1, allowing pressure toequalise on both sides of the piston 10. With equal pressure butun-equal areas exposed to the pressure, the piston 10 is then forcedclosed again.

In the embodiment of FIGS. 1 to 4. the valve utilises a return spring18. However, as illustrated in FIGS. 5 and 6, there is anotherconfiguration of the apparatus that achieve different but desirableperformance objectives. When configured or assembled without the mainreturn spring 18 as illustrated in FIGS. 5 and 6, the valve most closelyreplicates the behavior of the factory-fitted bypass valve, in that itoperates only in two states, either open as in FIG. 6 or closed FIG. 5.This configuration ensures the quietest possible operation, but stillwith the ability to open and close reliably even under higher boostpressure and temperature.

However, when the main return spring 18 is used, the main return spring18 influences the size of the opening created by the piston 10 inresponse to the boost pressure present in the intake tract andcommunicated by the diversion aperture 4.1. If boost pressure is low,the piston 10 only opens a small amount of bypass opening, with the keyobjective being to vent only enough air to prevent pressure spikes. Asthe boost pressure is reduced by the action of bypassing, the piston 10closes the diversion aperture 4.1 or decreases the size of the bypassopening, until there is no mere pressure and the piston 10 fully closesthe diversion aperture 4.1, even when the ECU is energising the solenoidcoil 2. If boost pressure is high when the ECU energises the solenoidcoil 2, the piston 10 will open further than when the pressure is lower,to allow more air to recirculate. In this situation the size of thebypass passage or opening can be described as variable or dependent uponthe amount of boost pressure to be diverted, unlike some of the priorart systems where the amount of opening of the valve is the same at allpressures due to the length of stroke of the direct acting solenoid.

In this way, the piston to is given a second means or parameter by whichits opening stroke length is controlled. By opening only enough toprevent pressure spikes when the throttle is closed, but not completelyevacuating the intake tract, turbo lag can be minimised. This means thatthe embodiment of FIGS. 1 to 4 may be preferable when better performanceis required but with it may come a slight increase in operational noise.

Key benefits of an after-market embodiment of the apparatus andmethod: 1. improved operation even under increased boost and operatingtemperature conditions; 2. simplified apparatus ensures a low-costsolution that is easy to install; 3. fast operational speeds becausethis apparatus does not require manifold vacuum to open, nor does itneed vacuum hoses to be connected that would delay the pressure/vacuumsignals; 4. utilizes the factory-supplied solenoid coil which means thebenefits of the ECU control signal are retained, and a functioningsolenoid coil is not wasted.

While the above description describes an after-market modification so asto use existing mounting systems and the like, it will also beunderstood that the diverter valve of the invention can be provided asan OEM diverter valve instead of the existing OEM diverter or bypassvalves.

Key benefits of an OEM inventive embodiment of the apparatus andmethod: 1. reliable or improved operation even under increased boost andoperating temperature conditions; 2. fast operational speeds becausethis apparatus does not require manifold vacuum to open, nor does itneed vacuum hoses connected that delay the pressure/vacuum signals.

FIG. 12 illustrates a block diagram of the method of operation of thevalve system of FIGS. 1 to 6 and 11 which will be described below. InFIG. 12 the items numbers represent the following block diagram steps:

-   1000—solenoid coil is not energised-   1010—piston 10 and plunger 13 are in a closed position-   1020—pressure acting on piston face is transmitted to the chamber    behind the piston via the transfer aperture 12 in the piston face-   1030—pressure on downstream side of piston acts on an area 27%    larger than the area on which the pressure acts on the upstream side    of the piston-   1040—resultant force holds piston in closed position preventing    turbo bypassing-   1045—throttle closed input-   1050—solenoid coil energised by engine's ECU output-   1050—plunger 13 retracts opening control aperture 6 in chamber wall    5-   1070—air flows through transfer aperture(s) which effectively    reduces pressure on the downstream surface area with respect to said    transfer aperture-   1030—pressure differential overcomes return spring bias if return    spring present and or friction between chamber wall and piston and    or inertia of the piston-to push piston to open the diverter passage-   1090—turbo air enters bypass or diverter passages through the valve-   1100—pressure in turbo piping reduces to zero as a result of    bypassing-   1110- resultant force from pressure differential reduces to zero-   1120—return spring overcomes reduced force differential and moves    piston to closed position and turbo bypassing ceases-   1095—engine throttle open-   1096—solenoid coil de-energised by ECU unit-   1097—return spring pushes plunger 13 to close control aperture 6 in    chamber wall 5-   1098—pressure equalises on both sides of piston resulting in a 27%    force differential which biases the piston to the closed position-   1099—resultant force and mam return spring combine to keep piston    closed thereby ceasing diversion or bypass conditions.

The operation of the pilot or valve operating system as described aboverelies on a number of specific design criteria to functionappropriately, as described below.

When the solenoid energises and the plunger 13 is retracted there byallowing airflow through the control aperture 6, and subsequentlythrough chamber 7 and transfer hole/holes 8 must be greater than theairflow through the piston transfer aperture 12, such that pressurebehind the piston 10 will be reduced to close to zero.

In a preferred embodiment the piston transfer aperture 12 has a diameterof approximately 2 mm, while the control aperture 6 has diameter ofapproximately 5 mm, and there are four transfer passages 8 each ofapproximately 3 mm in diameter. The cross-sectional area of the fourtransfer passages 8 is greater than that of the control aperture 6,thereby ensuring they create no additional downstream flow restrictionor back pressure due to turbulence and/or the length of the transferpassages 8. Because the piston transfer aperture 12 is concentric to thecontrol aperture 6, air passing through the piston transfer aperture 12creates a jet that is directed into the control aperture 6, whichentrains air from the surrounding chamber 5.1 which results in a slightvacuum in the chamber 5.1, thereby aiding the piston 10 moving to theopen condition.

The plunger 13 forms part of the path that air must take to evacuate thepiston chamber 5.1. and therefore the retract distance of the plunger 13also plays a role in determining the total flow capacity of the controlaperture 6. The plunger 13 must retract sufficiently so as not torestrict flow through the control aperture 6. A preferred retractdistance of 1 mm to 2 mm will satisfy this.

The surface area that pressure gets to act upon on the upstream face ofthe piston is dictated by the diameter of the raised bead 11.1 of themoulded face seal 11. In the closed position, the raised bead 11.1contacts the floor 9.1 (see FIG. 1) of the bypass path 9 which surroundsthe upper rim of the diversion aperture 4.1, so the pressure only actson the area enclosed by the bead 11.1. When the plunger is in the closedposition, pressure on both sides (upstream and downstream of transferaperture 12) of the piston is equalised, but on the back of the piston10 the pressure acts on the entire area of the piston outer diameter,which therefore creates a resultant force pushing the piston 10 closed.

For the embodiment described above the preferred bead diameter of 19.5mm can be utilised, while a piston outside diameter of 22 mm is alsoutilised, resulting in a face surface area (upstream) to piston surfacearea (downstream) ratio of 1:1.27, when calculated with the surface areaof the transfer aperture 12 removed from the available surface areas. Inan alternative embodiment a bead diameter of 21.5 mm can be utilisedwith a piston outside diameter of 24 mm, however this will result in aface surface area (upstream) to piston surface area (downstream) ratioof 1:1.247, when calculated with the surface area of the transferaperture 12 is removed from the available surface areas.

Another parameter to be designed for is the speed at which the piston10, will move from a closed to an open position. It is found that theparameters selected above will produce an appropriate speed of thepiston 10 for effective opening of the diverter passage as a replacementfor a factory solenoid diverter valve such as that manufactured byPierburg for Volkswagen/Audi, where the valve of FIG. 7 has part numberof 06F 145 710 G—commonly referred to by the Audi/VW community as the“Revision G” model. This valve is used on some Golf GTI, as well asother Audi/VW/Skoda models that share the same engine. BMW, Porsche,Peugeot and Mercedes also use a similar valve made by the same company.

As illustrated in FIG. 7, the standard direct actuating solenoid valvehas a mounting flange 3, and in this is located the valve piston whichis pushed shut by the return spring 15 of the solenoid. When solenoid isenergised by the ECU the direct coupled actuator rod opens the diversionpath.

Illustrated in FIGS. 8 and 9 are perspective views of the valve body 1of previous Figures, showing three mounting holes 1.1, which passthrough the valve body, while on a lower face a circular O-ring channel1.2 is provided so as to receive an O-ring to seal with the uppersurface of the mounting flange 3. Whereas in FIG. 9 there is visible inthe upper side the chamber 7 and the entrance location or apertures ofthe four transfer passages 8. Also present is a circular flange 1.3 tosubstitute for the material of the inserted chamber 9.3 of the factoryvalve of FIG. 7, and a cylindrical flange 1.4 to provide the cylindricalwall of the chamber 7.

While the above description and drawings show an O-ring seal 16 on theend of the plunger 13 it will be readily understood that the seal 16could be positioned on or around the control aperture 6.

The valve body 1, can be manufactured from any appropriate material andany appropriate method of manufacture. While most preferred is machiningthe valve body 1 from aluminium, or other metals such as brass orstainless steel could be used or plastic; or it could be injectionmoulded in polymeric material, die cast or made from sintered metals.Metal deposition techniques could also be used and possibly 3D printingdepending upon available polymers for such printing.

The piston 10 can be made from any appropriate material includingaluminium, stainless steel or appropriate polymeric materials or metals.

Diverter valves as described above are commonly found in one of twolocations, one is on a mounting flange that forms part of a superchargeror turbo compressor cover and includes a passage for incoming boostpressure, and one for the recirculation path. A second location used isa cast or machined mounting flange with the same inlet and outletfeatures but connected remotely to the intake via hoses.

While the above description is directed to embodiments which utilise apre-existing solenoid to open or close the control aperture 6 or an OEMvalve which uses a solenoid to do the same, it will be understood thatother motive power means to open and close the control aperture 6 can beutilised such as pneumatic operation, whereby a negative pressure in theinlet tract is used to provide motive power to move a control valvemember to take the place of the O-ring seal 16 and plunger 13.

Illustrated in FIG. 11 is another embodiment where the diverter valvesystem has a has two discrete body parts, so as to allow the location ofthe “upper” or first or actuator body part at one location in an enginebay and the “lower” or second or valve body part to be located on theturbocharger compressor or other component of the engine's intake tractat a second location in an engine bay. Like parts with the embodiment ofFIGS. 1 to 6 have been like numbered. This embodiment of FIG. 11 isparticularly advantageous in instances where the engine bay is organisedsuch that there is not much space above the turbocharger compressor orother component of the engine's intake tract on which the diverter valvemay be mounted.

In the split system of FIG. 11, the aperture 6 is effectively parted sothat the aperture 6 is on the remote upper or first or actuator body1.2, which connects to the port 6.1 on the lower or second or valve body1, by means of tube 6.2. Whereas a single transfer passage 8 is split sothat the lower or second or valve body 1 has a passage end 8.3 at theturbocharger compressor or other component of the engine's intake tract,while the remotely located body 1.2 has the other passage end 8.1 of thetransfer passage 8, with ends 8.3 and 8.1 being connected by tube 8.2.The tubes 6.2 and 8.2 are a silicone rubber tubing which are capable ofwithstanding the boost pressure which may be present in the turbochargersystem. Typical silicone vacuum hoses used for such purposes can readilywithstand over 50 psi, but a hose's characteristics can be selecteddepending upon the conditions prevalent in a turbo charging system towhich the embodiment is to be applied. In the embodiment of FIG. 11 onlya single transfer passage 8 is provided so as to minimise the number oftubes 8.2 that need to be connected, thus also minimising install time,length of tubing required and any additional clutter around the divertervalve system components.

White the above embodiments describe the use of a bypass path in thediverter valve system, it will be understood that instead of a bypasspath, the diverter system may divert to atmosphere.

In this specification, terms denoting direction, such as vertical, up,down, left, right, etc. or rotation, should be taken to refer to thedirections relative to the corresponding Figure rather than to absolutedirections unless the context require otherwise.

Where ever it is used, the word “comprising” is to be understood in its“open” sense, that is, in the sense of “including”, and thus not limitedto its “closed” sense, that is the sense of “consisting only of”. Acorresponding meaning is to be attributed to the corresponding words“comprise”, “composed” and “comprises” where they appear.

It will be understood that the invention disclosed and defined hereinextends to all alternative combinations of two or more of the individualfeatures mentioned or evident from the text. All of these differentcombinations constitute various alternative aspects of the invention.

While particular embodiments of this invention have been described, itwill be evident to those skilled in the art that the present inventormay be embodied in other specific forms without departing from theessential characteristics thereof. The present embodiments and examplesare therefore to be considered in all respects as illustrative and notrestrictive, and all modifications which would be obvious to thoseskilled in the art are therefore intended to be embraced therein.

1-29. (canceled)
 30. A turbo or super charged intake tract divertervalve having a body comprising: a mounting flange having at least onemounting aperture there through; a generally cylindrical chamber formedin said body which is configured to receive a valve member; said valvemember being generally cylindrical with a substantially closed end atone end, said substantially closed end having an aperture through theclosed end; said body further comprising at least one transfer passagethere through, the or each transfer passage ending in a port formed insaid body; said valve member having a face seal which is bonded oradhered to said substantially closed end.
 31. A valve as claimed inclaim 30, wherein said substantially closed end of said valve memberincludes a circumferential bead.
 32. A valve as claimed in claim 31,wherein said face seal and said circumferential bead are integrallyformed of silicone and bonded to said valve member.
 33. A valve asclaimed in claim 30, wherein said face seal includes a circumferentialbead.
 34. A valve as claimed in claim 33, wherein said face seal ismanufactured of silicone and bonded or adhered to said valve member. 35.A valve as claimed in claim 30, wherein said face seal is manufacturedfrom silicone and bonded or adhered to said valve member.
 36. A valve asclaimed in claim 30, wherein said face seal is bonded silicone.
 37. Avalve as claimed in claim 30, wherein said valve body includes afrustoconical portion extending away from said mounting flange; and saidgenerally cylindrical chamber is formed in said frustoconical portion.38. A valve as claimed in claim 37, wherein said at least one transferpassage is formed through said frustoconical portion.
 39. A valve asclaimed in claim 37, wherein said port of said at least one transferpassage is elliptical in shape.